- Phosphorus Ultra Low Range Colorimeter HI736 Hanna Checker - Marine Water
Monitoring phosphorus concentration in saltwater is important because it can cause corrosion if levels are too high. The Hanna HI736 Checker HC Handheld Colorimeter for Phosphorus ULR bridges the gap between simple chemical test kits and professional instrumentation. Accurate, affordable and easy to use. First, zero the instrument with your water sample. Next, add the reagents. Last, place the vial into the Hanna Phosphorus Checker, press the button and read the results. Done.
- Easier to use and more accurate than chemical test kits
- Large, easy to read digits Auto shut-off
- Dedicated to a single parameter
- Designed to work with HANNA's reagents
- Uses 10 mL glass cuvettes
- Small Size, Big Convenience
- Fits in the palm of your hand
- Range: 0 to 200 ppb
- Resolution: 1 ppb
- Accuracy: ±5 ppb ±5% of reading
- Light Source: LED @ 525 nm
- Light Detector: Silicon photocell
- Environment: 0 to 50°C (32 to 122°F); RH max 95% non-condensing
- Battery Type: (1) 1.5V AAA
- Auto-off: After 2 minutes of non-use and 10 seconds after reading
- Dimensions: 81.5 x 61 x 37.5 mm (3.2 x 2.4 x 1.5")
- Weight: 64 g (2.25 oz.)
- Method: Adaptation of Standard Method for Examination of Water and Wastewater, 20th edition, Ascorbic Acid method
Which is better to test for, Phosphate or Phosphorus? Want to find out - Click Here
Easy to use By Gina on 10/8/2018Gina would recommend this product to a friendHave read reviews on timer running out before dissolving powder. What I do is to use both vials provided. One for just saltwater and the other to mix powder BEFORE starting test. Once the powder is dissolved I start test. Turn on, calibrate (C1) with just water vial and switch to vial with dissolved powder (C2). No problem done in minutes. I've been using HI713 for over 3 years for tank and to double check my DI water just in case filters and resin needed to be changed. Have since upgraded to HI736.
Stupid test design errors By Wally on 8/23/2018Wally wouldn't recommend this product to a friendThis product has an obvious design errors - the time allowed to mix the reagent added, and the method of adding *all* reagent to the test vial. The product has an auto shut-off timer that is set to time recommended to mix the reagent, leaving *zero* seconds to remove the vial, add reagent and return the vial. An extra 30-45 seconds would be really useful, and I can't believe that the product managers and designers didn't see this ahead of time. Packaging of the reagents also makes it difficult to get all of the dose into the vial without spilling. Which is made even worse because you have to hurry to beat the shut-off timer. Why didn't the manufacturer look at these before releasing the product to the market?
Including more reagents in the base unit might be helpful. Also some sort of funnel would aid in getting the reagent into the small opening of the vial.
Hanna tech support forwarded a YouTube video suggesting one method of speeding up your mixing process and improving the adding of the reagent. Why isn't this part of the instructions provided?
Thoughtful product design and solutions to these issues offered with the product really could make this a good product. Then again maybe this is they way Hanna expects to increase their margin, through customers wasting reagent via uncompleted tests!
Some modification needed but overall a good device By Frank on 8/8/2018Frank would recommend this product to a friendThis device makes checking phosphorus much much easier. But after you add the reagent, only shake for 90 seconds as opposed to 2 minutes because the machine will automatically turn itself off in exactly 2 minutes. Not sure why the manufacturer haven’t thought about it.
Very frustrating device times out prior to completion of test By Luke on 6/25/2018Luke wouldn't recommend this product to a friendWell I burned through 4 of the six reagent packets (six really?) getting my speed testing regimen down with hard to handle packets of reagent. This is poor design; change the timeout programming so people don't have to hurry through the process.
Great Product By Esquare on 5/13/2018Esquare would recommend this product to a friendI have used the Hannah Low Range for a while and always got "0" so i tried this ULR and am now getting ".06" so for me it's working great!
Another great investment ! By Jason on 2/23/2018Jason would recommend this product to a friendYet another great investment along with the hanna ALK checker. Accurate, buy more regent kits though cause they don't give you a lot which I don't understand why. Remember the formula - reading x 3.066 / 1000 to get your number. I give it 4 stars cause they don't give you a lot of regent blaaaa
Works well, when you are careful By Matthew on 1/31/2018Matthew would recommend this product to a friendI too do the 2 cuvette trick with these, as getting it back into the checker in time to check it before it shuts off has been tricky for me so far. I wish that the checkers that have longer sit times such as this would not shut off as quickly, but otherwise, following the directions, making sure everything is clean, etc., provides accurate results.
Phosphorus and Alkalinity Checker (Hanna) By Jeffrey on 12/11/2017Jeffrey would recommend this product to a friendI have read the reviews of this unit and the criticisms. I understand what people say but I think when each test is planned correctly and prep work done before each test is begun, the issues were non existant and when the adjusted results were compared to a Red Sea Pro the results were accurate without the need to guess if the result was .01, .02 or .03 because the color was a shade lighter then the color on the wheel for .04. The consistency and repeatably were very good when the procedure for conducting the test was kept the same each time. It is important to not let the reacted sample sit for too long as the accuracy is greatly affected but for those shooting for ULNS its a must have! .
Meh By Ron on 12/11/2017Ron would recommend this product to a friendI'm rating this a 3 because..In the picture here you see a package of reagents for 25 test, but in reality you only get enough reagents for 6 tests...so you might as well order reagents when you buy this...Meh!!!
Works great once you get the hang of it By John on 11/28/2017John would recommend this product to a friendYes, getting all the reagent out of the package is a little annoying, but if you follow the instructions it's very doable. The annoying part is timer between the initial baseline reading (prior to adding reagent) isn't long enough to mix the reagent to get it back in the tester before timing out and shutting off. This pretty much forces you to use one vial for the baseline and one to mix the reagent in. This goes against best practices for testing, but in the end it works just fine. So once you figure out the procedure and the math to convert the reading to phosphate, this tester works great for reading ultra-low levels of phosphate that other test kits just can't do.
A good product - but By Ohwell on 11/3/2017Ohwell wouldn't recommend this product to a friendThe product seems to work well - IF you can get the Reagent out of the packet. For something that is measured in PPB, it is ridiculous the way the reagent is packaged. It is completely random as to whether one gets the reagent out completely out. Other companies have plastic pockets/containers for reagents (HACH) - the way this is packaged (a very small amount of reagent in a packat that could contain 50x). Ridiculous number of packets included in the first unit (small) and wasted a couple just making sure all the powder was 'out' of the packet. Its the best 'low PO4 test' but overall its horrible
VERY accurate, but tricky to use at first By Randall on 8/9/2017Randall would recommend this product to a friendOver the past couple of months, I've purchased and evaluated most of the hobbyist-level marine test kits from Red Sea, Salifert, Elos, Hanna, Nyos, SeaChem, Giesemann, Lamotte, and Hach, and then compared them to results from simultaneous water samples sent to Triton Labs for spectroscopy.
This colorimeter is hands down the most sensitive and most accurate hobbyist device for measuring phosphorus, at least at low levels. For example, it will give me a reading of 7 when a corresponding sample sent to Triton Labs comes back as 6. Hanna's very similar phosphate colorimeter for some reason is not quite as sensitive, sometimes reading zero when there is actually a very small amount of phosphate present.
Aside: This device measures phosphorus in ppb. A rough conversion to the phosphate we're mostly more familiar with is easy to do in your head. Multiply by 3 and move the decimal point 3 places. So, a phosphorus reading of 10 is a phosphate of .03, a reading of 20 is phosphate .06, and so on.
Unfortunately some features of this device seem designed for people to fail to perform the test properly, requiring repeat with use of more reagents (Hanna is stingy with reagents in general). Some of these have been mentioned by another reviewer, but here are my tips to doing the test correctly every single time.
1. Open the reagent packet first. Tamp it down, tear across the mid portion, then open one seam. You've made a little dispenser out of it. Put it aside.
2. (Optional) Buy some small plastic perfume funnels off Amazon. They will let you quickly pour the powdery reagent into the small mouth of the test cuvette, ensuring that none is lost. They are also useful for some other Hanna colorimeters.
3. Make sure there are NO tiny bubbles on the inside of the test cuvette, or smudges on the outside, any time it goes inside the colorimeter.
4. After doing the blank, remove the cuvette and add the reagent (with the funnel) promptly. Cap it and shake it fairly vigorously for 90 seconds, not 2 minutes as the instructions say. Make sure there is no floating particulate matter visible when you put it back in the device.
5. Remember to HOLD the button for the 3 minute timer; if you just press and release, you screwed up and have to repeat the test. Whether you use the built-in timer or not, set a separate timer for 3 minutes, because the built-in one makes no sound when it expires and runs the test, and the device will then turn itself off a few minutes after that. Super easy to miss if you're doing other stuff (like, oh, running other tests).
Why is there a timer? Is this the time it gives me to Dissolve the powder? Or does the sample have to be in the colorimeter the whole time?
Thanks for the question and have a great day!
Which checker should I use for a reeftank the hi713 or hi736 to check for phosphate?
We use the Hi713 in most cases as it is easier to use and read over the phosphorus which requires additional calculation to convert to phosphate.